Optimized sensor networks using bluetooth

Abstract

A system and method for reducing the probability of collisions in a Bluetooth wireless sensor network is disclosed. The system and method utilize Periodic Advertising with Response to receive status information from the plurality of wireless sensor devices. Therefore, rather than sending the Sensor Status message at random times, the wireless sensor devices are all assigned a response slot in one of the subevents. The relay device receives all of the sensor status messages and forwards the information to the next hop device using measurement collection packets. In some embodiments, the relay device compacts the information before transmitting the measurement collection packets.

What is claimed is: 
     
         1 . A method of reducing data collisions in a Bluetooth wireless sensor network, wherein the Bluetooth wireless sensor network utilizes periodic advertisements with responses, wherein each of a plurality of wireless sensor devices in the Bluetooth wireless sensor network is assigned a response slot, the method comprising:
 wirelessly transmitting, from a relay device, at least one subevent start packet;   receiving, at the plurality of wireless sensor devices, the at least one subevent start packet;   performing, at each of the plurality of wireless sensor devices, a measurement to obtain measurement data;   transmitting measurement response packets from each of the plurality of wireless sensor devices to the relay device during a respective assigned response slot, wherein the measurement response packet contains the measurement data; and   receiving, at the relay device, the measurement response packets from the plurality of wireless sensor devices.   
     
     
         2 . The method of  claim 1 , further comprising:
 generating, at the relay device, one or more measurement collection packets using information from the measurement response packets; and   transmitting the one or more measurement collection packets from the relay device to a next hop device.   
     
     
         3 . The method of  claim 1 , wherein the at least one subevent start packet is an AUX_SYNC_SUBEVENT_IND PDU (protocol data unit). 
     
     
         4 . The method of  claim 3 , wherein the at least one subevent start packet includes an indication of a type of sensor data requested. 
     
     
         5 . The method of  claim 4 , wherein the at least one subevent start packet includes a Sensor Get message. 
     
     
         6 . The method of  claim 1 , wherein the measurement response packet includes a Sensor Status message, contained within an AUX_SYNC_SUBEVENT_RSP PDU. 
     
     
         7 . The method of  claim 2 , further comprising compacting addresses of the wireless sensor devices, at the relay device, in the one or more measurement collection packets. 
     
     
         8 . The method of  claim 7 , wherein compacting of the addresses comprises creating an array of addresses. 
     
     
         9 . The method of  claim 7 , wherein compacting of the addresses comprises creating an address range. 
     
     
         10 . The method of  claim 2 , wherein the measurement response packet includes a Sensor Status message, containing a format, a Property ID, a length and the measurement data, and further comprising compacting the measurement data received from the wireless sensor devices at the relay device, in the one or more measurement collection packets. 
     
     
         11 . The method of  claim 10 , wherein compacting the measurement data comprises creating a data array, each element of the data array associated with one of the plurality of wireless sensor devices; wherein each element comprises the format, the Property ID, the length and the measurement data associated with a respect wireless sensor device. 
     
     
         12 . The method of  claim 10 , wherein all Sensor Status messages have a same format, length and Property ID, and wherein compacting the measurement data comprises creating a compacted data array, comprising a header including the format, the Property ID, the length and a data array comprising the measurement data from each wireless sensor device. 
     
     
         13 . The method of  claim 10 , wherein all Sensor Status messages have a same format, length and Property ID, and wherein compacting the measurement data comprises creating a compacted data array, comprising a header including a bitlength and the Property ID, and a data array comprising the measurement data from each wireless sensor device. 
     
     
         14 . A Bluetooth wireless sensor network, wherein the Bluetooth wireless sensor network utilizes periodic advertisements with responses, comprising:
 a plurality of wireless sensor devices; and   a relay device; wherein the relay device transmits at least one subevent start packet;
 wherein each of the plurality wireless sensor devices receives the at least one subevent start packet, performs a measurement to obtain measurement data and transmits a measurement response packet to the relay device during a respective assigned response slot. 
   
     
     
         15 . The Bluetooth wireless sensor network of  claim 14 , further comprising a next hop device; wherein the relay device receives a plurality of measurement response packets from the plurality of wireless sensor devices, and transmits one or more measurement collection packets to the next hop device. 
     
     
         16 . The Bluetooth wireless sensor network of  claim 15 , wherein the relay device compacts addresses of the plurality of wireless sensor devices in the one or more measurement collection packets. 
     
     
         17 . The Bluetooth wireless sensor network of  claim 15 , wherein the relay device compacts the measurement data received from the wireless sensor devices in the one or more measurement collection packets. 
     
     
         18 . The Bluetooth wireless sensor network of  claim 17 , wherein the measurement response packet includes a Sensor Status message, containing a format, a Property ID, a length and the measurement data, and wherein the relay device creates a compacted data array, comprising a header including the format, the Property ID, the length and a data array comprising the measurement data from each wireless sensor device. 
     
     
         19 . The Bluetooth wireless sensor network of  claim 17 , wherein the measurement response packet includes a Sensor Status message, containing a format, a Property ID, a length and the measurement data, and wherein the relay device creates a compacted data array, comprising a header including a bitlength and the Property ID, and a data array comprising the measurement data from each wireless sensor device.